First Generation of Batteryfree Cellphone!!!!

Don’t you ever felt frustrated and thought of throwing your phone away due to dying batteries in an emergency?? Here is some news, the recharging challenges with cellphones may get away from the new innovations from US. A team from the University of Washington have developed battery-free phone that can harness power from radiofrequency (RF) waves sent to it from a nearby base station. The phone not only harnesses the power it needs to operate from those waves, but can also place a voice call by modifying and reflecting the same waves back to the base station, through a technique known as backscattering.

The battery-free device prototype is built using commercial-off-the-shelf components on a printed circuit board. It can operate on power that is harvested from RF signals transmitted by a basestation 31 feet (9.4 m) away. Using power harvested from ambient light with tiny photodiodes, the device can also communicate with a basestation that is 50 feet (15.2 m) away. The team demonstrated that the prototype can perform basic phone functions such as transmitting speech and data and receiving user input via buttons. Using Skype, researchers were able to receive incoming calls, dial out and place callers on hold with the battery-free phone. 
One of the phone's key innovations is the use of analog rather than digital voice encoding, which the researchers say saves a substantial amount of power. Supplemental power to increase the device’s range comes from photodiodes, essentially tiny solar panels. Unlike a traditional cell phone which uses 800 milliwatts(tens of thousands of times more power), when making a call. The entire device consumes just 2 to 3 microwatts of power to place or receive a call.
The battery free phone takes advantage of tiny vibrations in a phone’s microphone or speaker that occur when a person is talking into a phone or listening to a call. An antenna connected to those components converts that motion into changes in standard analog radio signal emitted by a cellular base station. This process essentially encodes speech patterns in reflected radio signals in a way that uses almost no power. To transmit speech, the phone uses vibrations from the device’s microphone to encode speech patterns in the reflected signals. To receive speech, it converts encoded radio signals into sound vibrations that that are picked up by the phone’s speaker.
The UW phone is also half-duplex, that means there is a button that users need to press to switch between sending and receiving mode. A microcontroller manages the RF switch, connecting the microphone to the antenna when a user presses a button to talk, and connecting the earphones when the user wants to listen. It’s more similar to a walkie-talkie than a real cell phone. But I dont think, it wont be a technical hurdle to create a system that detects when the user is talking or not and make the switch between these two modes automatically. Hope researchers can fix phone's biggest drawback sooner.
There is a long way to go before it hits markets. Currently the phone has a basic touch-sensitive number pad and its only display is a tiny red LED that glows briefly when a key is pressed. The researchers are looking into equipping it with an e-ink display, which doesn't consume a lot of power as well as a low power camera. The team is also looking forward to improving it’s operating range and encrypting conversation to make it more secure.
In this scenario where phones have become the most important devices that virtually everyone uses and we all love to have a batteryfree smartphone. Its surely a major leap in moving beyond chargers, cords and dying phones and is also an incredible step towards technology. What do you think of a cell phone never dying on your hands in the future?